False-colour transmission electron micrograph of parvovirus particles. Parvoviruses are small (22 nanometres in diameter) and consist of a single- stranded DNA genome surrounded by an icosohedral protein capsid (coat). Parvoviruses replicate most extensively in tissues undergoing relatively rapid division. Disease is therefore often related to gut epithelium (causing enteritis in cats, dogs and mink) or bone marrow (causing panleucopenia in cats). Magnification: x35,000 at 35mm size, x200,000 on 8x6 inch print.